Firewall shut itself off NIS 2013

I was on a website and I noticed the Norton button in my toolbar had a red check. I opened NIS 2013 and in the SECURE button it said "unprotected" or something like that on the main page. I clicked on it and I got a green "ok" indicator. I had the latest auto update. I viewed security history and it showed:

firewall config updated 56 rules   no action required

firewall disabled  no action required

It did not re-enable the firewall. What is going on here? Software bug in the update process or do I have a virus?

Will a regular full system scan take care of it or do I have to do more?

Windows Process Explorer shows MS and other known tasks running. I have Win XP SP3.